This invention relates to surgical staplers, and more particularly to improved anvils for use in surgical staplers of the type in which one or more U-shaped surgical staples are driven through body tissue and against an anvil to deflect, crimp, or clinch the ends of the staple legs and thereby secure the tissue.
Surgical staplers having a wide variety of configurations are known. This invention relates to the general type of surgical staplers in which the tissue to be stapled is positioned between a staple holding assembly and an opposing anvil assembly, and one or more generally U-shaped staples are driven from the staple holding assembly, through the tissue, and against the anvil to deflect, crimp, or clinch the ends of the legs of the staples and secure the tissue. (In relation to forming a staple, the words "deflect", "crimp", and "clinch" are used interchangeably herein to refer to deformation of the staple by the anvil.) Examples of this general type of surgical stapler are the linear closure staplers shown in Green et al. U.S. Pat. No. 3,494,533, the circular anastomosis staplers shown in Conta et al. U.S. Pat. No. 4,304,236 and the linear anastomosis staplers shown in Green U.S. Pat. No. 3,499,591.
In staplers of the general type described above, it is conventional to provide separate anvil slots at each staple forming location. This makes it necessary to maintain relatively stringent alignment between the staple holding assembly and the anvil to assure that the staples enter the anvil slots correctly for proper crimping or clinching. It is extremely important that every staple be formed properly, because any incompletely or improperly formed staple can leave a gap in a wound closure, with the possibility of such adverse consequences as improper or prolonged healing of the wound or leakage of blood or other body fluid or body contents through the wound. The necessity of maintaining a high degree of alignment between the relatively movable staple holding assembly and anvil assembly may contribute significantly to the complexity of the instrument and to the cost of manufacturing and maintaining it.
In view of the foregoing, it is an object of this invention to improve and simplify surgical staplers of the type described above.
It is a more particular object of this invention to substantially eliminate at least some of the requirements for exact alignment in surgical staplers of the type described above.